Electric valve circuit



Jan. 2, 1945.

A. SCHMIDT, JR

ELECTRIC VALVE CIRCUIT Filed March 18, 1942 PEAK/N5 TIAMSFORMEI? 6 4 z; y 5 j 0 "LL m F r I 'r /7 a 1/1 a nu J V 7 2/ 2d ,3

PEAK/N6 b mnusrannm Inventor:

August Schmidt Jr.

Hi s A torney.

Patented 2,' 1945 ELECTRIC VALVE CIRCUIT August Schmidt, J r., Niskayuna, N. Y., assignor to General Electric Company, a corporation of New York Application March 18, 1942, Serial No. 435,129

15 Claims.

My invention relates to electric valve systems and more particularly to control circuits for electric valve apparatus of the type employing an ionizable medium such as a gas or a vapor.

Electric valve means employing self-reconstructing type cathodes, such as mercury pool cathodes, have been found to afford decided advantages in those applications where large amounts of current are transmitted by an associated load circuit. In accordance with the teachings of my invention described hereinafter. I provide new and improved electric control circults for electric valve means of this type, andcircuit for controlling the conductivity of electric valve means using a self-reconstructing type cathode and which comprises ignition means such as an immersion-ignite! control member assoriated with the cathode.

Briefly stated, in the illustrated embodiment of my invention I provide a new and improved control system for electric valve apparatus of the typ which employs a self-ieconstructing type cathode. such as a mercury pool cathode, and in which the time of initiation of current flow between the anode and cathode is accurately determinable by controlling the potential of an auxiliary control electrode or a ballie. Unidirectional impulses of current are transmitted to the ignition means. which may be an immersionigniter control member in contact with the cathode, by means of a unidirectional conducting device, such as a dry rectifier or a copper-oxide type rectifier. In order to maintain the potential of the control member at the same potential as the cathode, thereby preventing transmission of appreciable inverse current between the cathode and the control member during thenegative half cycles of voltage of the source 01' excitation current. I provide equalizing means connected be tween the source of alternating excitation current and the control member.

For a better understanding of my inv ention.

reference may be had to the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims. The single figure of the drawing diagrammatically illustrates an embodiment of my invention as applied to a biphase rectifier and which comprises electric valve translating apparatus connected between an alternating current supply circuit and a direct current load circult.

Referring nova to the single figure of the drawmg, I have there illustrated my invention as applied to an electric valve translating or converting system connected between an alternating current supply circuit I and a load circuit such as a direct current load circuit 2. The translating apparatus may include a transformer 3 and a pair of electric valve means 4 and 5 which operate as a biphase rectifier for transmitting unidirectional current to the load circuit.

Electric valve means 4 and 5 are preferably of the type employing an ionizable medium, such as a gas or a. vapor, and each comprises an anode 6, a self-reconstructing cathode such as a mercury pool cathode l, and ignition means which may be of the lmmersion-igniter type such as an immersion-igniter control member 8 constructed of a material, such as boron carbide or silicon carbide having an electrical resistivity substantially large compared with that 01' the mercury of the associated pool. An extremity of the immersion-igniter control member 8 may extend into the mercury. Each of the electric valve means 4 and 5 also may comprise a relieving or transfer anode 9. In order to control the times of initiation'of current flow between the anodes 6 and the cathodes I after the initiation of arc discharges by control member 8, I provide battle or control electrodes "I which are preferably within the vicinities of the respective anodes 8, and which may be constructed to enclose substantially the anodes 6.

As a means for supplying excitation current to the control members 8 of electric valve means 4 and 5, I provide an excitation circuit which is energized from a suitable source of alternating current H. The source of current for energizing the excitation circuit, of course, may be derived from the supply circuit i through suitable phase shifting means, if desired. I connect to e source H means for producing periodic or al rnating voltages of peaked wave form. This means may comprise a transformer I! having a primary winding is and winding means, such as a secondary winding, for supplying peaked alternating voltages displaced substantially its electrical degrees with respect to each other. This secondary winding means may comprise winding sections iIa and III: having electrically displaced terminal connections it and H, and a connection II electrically intermediate the terminal connections. The intermediate connection II is connected to the cathodes I or electric'valve means I and I.

In order totransmit to the control members I or electric valve means I and I impulses oi unidirectional current of peaked wave form and for initiating arc discharges within the electric valve means by establishing cathode spots upon the surface oi the mercury pool cathodes I, I provide rectiiiers i1 and II which are preferably of the contact or dry type such as that disclosed and claimed in U. 8. Letters Patent No. 1,640,335, granted August 23, 1927. upon an application of Lars 0. Grondahl. Relieving anodes I are connected to the terminals II and II, respectively. of winding sections Na and IIb, and I connect transfer resistances II and II in series relation with the rectiners l1 and II so that upon initiation of arc discharges within the respective electric valve means, the potential of ,the relieving anodes is substantially raised, thereby eilecting the transmission of the greater portion of the excitation current irom control members I to relieving anodes I and accordingly reducing the duty imposed on control members I.

As a means for maintaining the control members I at substantially the same potentials as the associated cathodes 1 during the respective inverse half cycles oi voltage of source H or, in other words, to prevent the flow of inverse current from cathodes I to control members I during the negative half cycles of voltage produced by winding sections Na and "b, I provide equalizing means connected to the winding sections lIa and Nb. This equalizing means may comprise resistances Ii and II which are connected between electrically displaced points of the secondary winding means of transformer II and the control members I of the electric valve means. The magnitude of the resistances Ii and II is preferably equal to the average inverse resistance of the dry rectiiiers l1 and II. More particularly, resistance Ii is connected between control member I of electric valve means I and the terminal II of winding III). In like manner, resistance II is connected between control member I of electric valve means I and the terminal II of the winding section lIa. Periodic voltages ar impressed on the control electrodes II oi electric valve means I and I in order to render the electric valve means conducting alter nately. and to control the time during the cycles of voltage of circuit I at which current flow is initiated between the respective associated anodes I and cathodes I. I provide a transformer II energized from a source 0: alternating current of the proper frequency. Transformer II comprises a secondary winding II'having a neutral connection II. If desired, tramiormer II may be energised from the alternating current circuit I through a phase shifting device II. The phase shifting device II serves to control the phase of the periodic voltages impressed on control electrodes II and,' hence, controls the magnitude of the current transmitted to the load circuit.

Suitable potential biasing means. such as a battery II, may be connected between the cathode I and the neutral connection II of transformer II in order to impress on the control electrodes II a negative unidirectional biasing poten tial. I connect between the secondary winding II or transiormer II means tor assuring the transmission of sumclent positive control current to the electrodes II, thereby assuring the positive initiation of arc discharges between associated anodes I and cathodes I. This means may comprise unidirectional conducting devices or rectiflers I1 and II which are connected, respectively, in parallel with impedance elements such as resistances II and II. 1

Transformer II may also be a peaking transformer, so that the impulses of postive current transmitted to the control electrodes II are of distinct or sharp wave form thereby increasing the precision of control of the electric valve means I and I.

The operation of the embodiment of my invention illustrated in the single figure of the drawing will be explained by considering the system when it is operated as a biphase rectifier to transmit unidirectional current to the load circuit 2. The peaking transformer U, by virtue of the windings lIa and III), transmits unidirectional impulses of current to the control members I of electric valve means I and I alternately at times displaced substantially 180 electrical degrees relative to the voltage of the circuit I. These unidirectional impulses are transmitted to the control members I through the rectifiers ll.

II and associated resistances II, II respectively. Considering in particular the ignition of the electric valve means I, upon the transmission oi a unidirectional impulse of current to the control member I as soon as a cathode spot and incident ionization of the mercury vapor is obtained. the increased flow of current through the resistance II raises the potential of the relieving anode I. thereby eilecting the transfer of the greater portion of the ignition or exciting current from the control member I to the relieving anode I. In

this manner, the duty imposed on control mem-' her I is reduced. The relieving anode I malntains the arc within the electric valve means until such time as a suitable positive voltage is impressed on the control electrode iI at which time the arc discharge is established between the anode I and the cathode I.

Control electrodes II are normally maintained by the battery II at potentials suiliciently negative to prevent the propagation of the are discharges to the anodes I. At predetermined times established by the phase position of the periodic voltage of peaked wave form produced by transformer II. the voltage produced by winding II attains a value which is sufiicient to overcome the effect or the battery II and raises the notentials of control electrodes II, thereby extending the arc dischargesto the anodes I. Referring particularly to electric valve means I, at the time when a positive impulse of voltage 01' peaked wave form occurs, a unidirectional impulse of voltage is impressed on the control electrode II or electric valve means I. This selective unidirectional energization or control electrode III is obtained by means of rectifier II. In like manner, positive impulses of voltage of peaked wave form will be impressed on control electrode ll of electric valve means I at intervals displaced 180 ele ri l es relative to the impulses impressed on electrode II of electric valve means 4.

Due to the parallel connection of rectiiiers I1 and .II and resistances II and II. respectively. the positive impulses which are supplied to the electrodes II are 02 substantially greater magnitude than the negative impulses, thereby assub' ing greater precision in control oi electric valve means 4 and I.

The amount of current transmitted by the electric valve converting system and the amount of current transmitted to load circuit 2 are controllable or adjustable by means or the phase shifter 28. As the phase oi the impulses oi voltage impressed on the control electrodes is advanced toward the beginning of the positive half cycles of anode-cathode voltage, the amount of current is correspondingly increased, and as the phase or the positive impulses is retarded the load current is decreased. It will be appreciated that the amount of current transmitted to the load circuit may also be determined by controlling the phase of the voltage produced by peaking transformer It, in which case. however, it will be understood that the voltages impressed on control members I and control electrodes it must be in substantial phase coincidence, or the potentials impressed on control electrodes It must lag those impressed on control members I.

While I have shown and described my invention as applied to a particular system oi connections and as embodying various devices diagrammatically shown, it will be obvious to those skilled in the art that changes and modifications may be made without departing from my invention, and I, therefore, aim in the appended claims to cover all such changes and modifications as tall within the true spirit and scope or my invention.

What I claim as new and desire to secure by letters Patent of the United States is:

1. In combination, an alternating current cincult, a load circuit, electric translating apparatus connected between said circuits and comprising electric valve means including an anode, a cathode, a control member of the immersion-igniter type associated with said cathode and a control electrode within the vicinity of said anode, means for supplying to said control member a periodic voltage to establish a cathode spot, and means for supplying to said control electrode a periodic voltage of predetermined phase displacement relative to the voltage of said supply circuit and comprising in series relation with said control electrode a parallel connected unidirectional conducting device and a resistance.

In om in ion. an alternating current circuit, a load circuit, electric translating apparatus connected between said circuits and comprising electric valve means including an anode, a cathode and a control member of the immersionigniter type associated with said cathode, and an excitation circuit for energizing said control member comprising a source of alternating current, transforming means energised from said source and including a winding section havinga pair of terminals and an intermediate connection. said intermediate connection being con nected to said cathode, means connected between one of said terminals and said control member and comprising a rectifier of the dry type for transmitting unidirectional current to said control member and a resistance connected between I the other terminal and said control member. 1

8. In combination, an alternating current circuit, a load circuit, electric translating apparatus connected between said circuits and comprising 7 electric valve means including an anode, a cathode and a control member or the immersionigniter type associated with said cathode, and an excitation circuit for energizing said control member comprising a source of alternating eurfill.

rent, transforming means including a winding section having a pair of terminals and an intermediate connection, said intermediate connection being connected to said cathode, means connected between one or said terminal connections and said control member and comprising a rectifier of the dry type for transmitting unidirectional current to said control member and a resistance connected between the other terminal and said control member and having a value substantially equal to the average inverse resistance of said rectifier for maintaining said control member at cathode potential during the negative half cycles of voltage of said source.

4. In combination, an alternating current circuit, a load circuit, electrictranslating apparatus connected between said circuits and comprising electric valve means including an anode, a cathode, a control member of the immersion-igniter type associated with said cathode and a transfer electrode, a source of alternating current comprising transi'orming means having a winding section provided with a pair of terminal connections and a connection intermediate said terminal connections, the intermediate connection being connected to said cathode, means for transmitting impulses oi unidirectional current to said control member comprising a resistance and a dry rectifier connected between one 01' said terminals and said control member, means for connecting said transfer electrode to said one terminal, and means for maintaining said control member at cathode potential during inverse halt cycles of voltage of said source and comprising a resistance connected between the other terminal and said control member, said resistance having a value equal to the average inverse resistance of said dry rectifier.

5. In combination, an alternatingcurrent circuit, a load circuit, electric translating apparatus connected between said circuits and comprising electric valve means including an anode, a cathode of the mercury pool type, an immersion-igniter control member in contact with said cathode and a control electrode within the vicinity of said anode, a source of alternating current comprising transiorming means having a winding section provided with a pair of terminals and a connection electrically intermediate said terminals for transmitting impulses oi unidirectional current to said control member to establish arc discharges within said electric valve means and comprising a dry rectifier connected between one of said terminals and said control member, means for maintaining said control member at cathode potential during the inverse half cycles of voltage of said source and comprising a resistance connected between said control member and the other terminal, and means connected to said control electrode for determining the time during the cycles of voltage of said alternating current circuit at which current ilow is initiated between said anode and said cathode.

6. In combination. an alternating current circult. a load circuit, electric translating apparatus connected between said circuits and comprising electric valve means including an anode, a cathode, a control member or the immersion-ignite! type associated with said cathode and a control electrode within the vicinity oi said anode, means for supplying to said control member a periodic voltage of peaked wave iorm comprising a source of alternating current and a peaking transformer having winding means, connected to said control member, and means i'or supplying to said control electrode a periodic voltage of predetermined phase displacement relative to the voltage the supply circuit and for controlling the time oi initiation of current flow between said anode and said cathode and comprising a unidirectional conducting device and a resistance in parallel with said unidirectional conducting device.

7. In combination, an alternating current circuit, a load circuit, electric translating apparatus connected between said circuits and comprising electric valve means including an anode, a cathode, a control member 0! the immerslon-igniter type associated with said cathode, a control electrode within the vicinity of said anode and comprising an ionizable medium capable of supporting an arc discharge, means for supplying to said control member a periodic voltage to establish cathode spots on said cathode, and means for controlling the time during the cycles of anodecathode voltage at which said electric valve means is rendered conducting and comprising a resistance and a rectifier connected across said resistance for increasing the flow 01' positive current to said control electrode. i

8. In combination, an alternating current circuit, a load circuit, electric translating apparatus connected between said circuits and comprising electric valve means including an anode, a cathode, a control member of the immersion-lgniter type associated with said cathode, a control electrode within the vicinity of said anode and employing an ionizable medium capable of supporting an arc discharge, means for transmitting to said control member periodic impulses of current of peaked wave i'orm to ionize said:medium, and means for energizing said control electrode to control the time during the hall. cycles of voltage of said alternating current circuit at which current how is initiated between said anode and said periodic voltage and means connected between said last mentioned means and said control electrode and comprising in parallel relation a unidirectional conducting device and a resistance.

9. In combination, an alternating current circuit, a load circuit, electric translating apparatus connected between said circuits and comprising electric valve means including an anode, a cathode, ignition means, a control electrode within the vicinity at said anode and employing an ionizable medium capable of supporting an are discharge, means i'or energizing said ignition means and for ionizing said medium only during halt cycles oi positive voltage of its associated anode, and means for energizing said control electrode to control the time during the half cycles 0! voltage of said alternating current circuit at which current flow is initiated between said anode and said cathode'and comprising means for producing a periodic voltage and means connected between said last mentioned means and said control electrode and comprising in parallel relation a rectifler and a resistance.

10. In combination, an aiternating current circuit, a load circuit, electric translating apparatus connected between said circuits and comprising electric valve means including an anode, a cathode, ignition means associated with said cathode, a control electrode, said electric valve means employing an ionizable medium capable of sup- I cathode and comprising means for producing a porting an arc discharge, means tor transmitting to said ignition means periodic impulses of cur- .rent of peaked wave form to ionise said medium,

and means for energizing said control electrode to control the time during the hall cycles 01 voltage 01 said alternating current circuit at which current flow is initiated between said anode and said cathode and including a transformer and means connected betweensaid transformer and said control electrode for transmitting positive impulses of current thereto and comprising in parallel relation a unidirectional conducting device and a resistance.

11. In combination, an alternating current circuit, a load circuit, electric translating apparatus connected between said circuit and comprising electric valve means including an anode, a cathode and a control member of the immersionigniter type associated with said cathode, and an excitation circuit for energizing said control member comprising a source of alternating current, transforming means energized from said source and including a winding section having a pair of electrically displaced connections and a connection electrically intermediate said pair of connections, said intermediate connection being connected to said cathode. means connected between one of said pair of connections and said control member and comprising a rectifier o! the dry type for transmitting unidirectional current to said control member and means connected between a point intermediate said control member and said rectifier and the other connection oi said pair for maintaining said control member substantially at the potential oi said intermediate connection during the inverse half cycles oi voltage 01 said source.

12. In combination, an alternating current circuit, a load circuit, electric translating apparatus connected between said circuits and comprising electric valve means including an anode, a cathode, a control member 01' the immersion-igniter type associated with said cathode and a control electrode, said electric valve means employing an ionlzable medium capable of supporting an arc discharge, means for energizing said control member to establish arc discharges within said electrlc valve means and comprising peaking means ment relative to the voltage of said control member to determine the time during the cycles of voltage or said alternating current circuit at which the flow or current between said anode and said cathode is initiated 13. In combination, an alternating current circuit, a load circuit, electric translating apparatus connected between said circuits and comprising electric valve means including an anode, a cathode, a control member of the immersion-ilniter type associated with said cathode. a relieving anode and a control electrode within the vicinity of said anode, said electric valve means employing an ionizable medium capable or supporting an arc discharge, excitation means for energizing said control member and comprising meanstor producing periodic impulses or voltage or peaked wave form to initiate arc discharge within said electric valve means, means for connecting said relieving anode to the last mentioned means, and means for impressing on said control electrode impulses of voltage oi peaked wave form in order to control the times during the cycles of voltage oi said alternating current said anode and said cathode.

14. In combination, an alternating current circuit, a load circuit. electric translating apparatus connected between said circuits and comprising electric valve means including an anode, a cathode, a control member or the immersionigniter type associated with said cathode, a relieving anode and a control electrode within the vicinity of said anode, means for impressing on said control electrode a biasing potential tending to prevent the transfer of current between said anode and said cathode, excitation means for supplying to said control member periodic impulses of current 01' peaked wave iorni to establish arc discharges within said electric valve means, means for connecting the last mentioned means to said relieving .anode, and means for impressing on said control electrode periodic voltages oi peaked wave form suflicient in magnitude to over. come the eiiect oi said biasing potential to control thereby the times during the cycles of voltage 20 od qaid alternating current circuit at which ourrent flow is initiated between said anode and said cathode. v

15. In combination, an alternating current circuit, a load circuit, electric translating apparatus connected between said circuits and comprising electric valve means capable oi supporting an arc discharge and including an anode, a cathode, immersion igniter means associated with said cathode for ionizing said medium and a control electrode, means for energizing said igniter means, means for impressing a biasing potential on said control electrode tending to maintain said electric valve means nonconducting, and means for impressing on said control electrode a periodic voltage of peaked wave form variable in phase displacement relative to the voltage 01' said immersion igniter means and sufficient in mashitude to overcome the effect 01' said biasing potential for rendering said electric valve means conducting.

AUGUST SCHMID I, Js.

CERTIFICATE OF CORRECTION Patent No. 2,366,561.

January 2, 19 5.

AUGUST SCHMIDT, JR.

It is hereby certified that rror appears in the printed specification of the above numbered patent requiring correction as'follows: Page 2, second column, line 12, for "postive" read --positive--;

page 1;, second column, line 146, claim 12, after "transmitting" insert -to-; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and scaled this 10th day of April, A. D. 1914.5.

(Seal) Leslie Frazer Acting Commissioner of Patents.

14. In combination, an alternating current circuit, a load circuit. electric translating apparatus connected between said circuits and comprising electric valve means including an anode, a cathode, a control member or the immersionigniter type associated with said cathode, a relieving anode and a control electrode within the vicinity of said anode, means for impressing on said control electrode a biasing potential tending to prevent the transfer of current between said anode and said cathode, excitation means for supplying to said control member periodic impulses of current 01' peaked wave iorni to establish arc discharges within said electric valve means, means for connecting the last mentioned means to said relieving .anode, and means for impressing on said control electrode periodic voltages oi peaked wave form suflicient in magnitude to over. come the eiiect oi said biasing potential to control thereby the times during the cycles of voltage 20 od qaid alternating current circuit at which ourrent flow is initiated between said anode and said cathode. v

15. In combination, an alternating current circuit, a load circuit, electric translating apparatus connected between said circuits and comprising electric valve means capable oi supporting an arc discharge and including an anode, a cathode, immersion igniter means associated with said cathode for ionizing said medium and a control electrode, means for energizing said igniter means, means for impressing a biasing potential on said control electrode tending to maintain said electric valve means nonconducting, and means for impressing on said control electrode a periodic voltage of peaked wave form variable in phase displacement relative to the voltage 01' said immersion igniter means and sufficient in mashitude to overcome the effect 01' said biasing potential for rendering said electric valve means conducting.

AUGUST SCHMID I, Js.

CERTIFICATE OF CORRECTION Patent No. 2,366,561.

January 2, 19 5.

AUGUST SCHMIDT, JR.

It is hereby certified that rror appears in the printed specification of the above numbered patent requiring correction as'follows: Page 2, second column, line 12, for "postive" read --positive--;

page 1;, second column, line 146, claim 12, after "transmitting" insert -to-; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and scaled this 10th day of April, A. D. 1914.5.

(Seal) Leslie Frazer Acting Commissioner of Patents. 

